This invention relates in general to a method and device for providing different levels or classes of packet delivery service in a packet-based network.
Today, Internet Protocol or xe2x80x9cIPxe2x80x9d networks such as the Internet currently support a single class of best-effort service to deliver digital information packets carried by the network between, for example, a remote access server (xe2x80x9cRASxe2x80x9d or Network Access Server xe2x80x9cNASxe2x80x9d) and a remote host. In a typical single class of service network, all information packets transmitted between source and destination RAS devices are treated as equal in priority. The network makes no differentiation or distinction between different packets and thus all packets are of the same priority and subject to the same network delivery latencies and delays.
Next-generation remote access servers will need to explicitly support multiple classes of service to implement new applications and services, such as live motion video or Voice-over-IP services that require real-time packet delivery performance. These classes of service may operate on a packet-by-packet basis and include options to differentiate the priority of packet forwarding and routing between packets on difference connections. Packet delivery classes of service can be based on pre-defined throughput, delay, jitter, and loss parameters. The network delivery option parameters are expected to be administratively initiated and enforced by the network on either a per-user or per-traffic-type basis.
For example, a network user may have an agreement with the network operator such that the network will stamp all of the users packets with a class of service defined by the particular per hop behavior (xe2x80x9cPHBxe2x80x9d) of the packet. Or, the PHB of the packet could be based according to the type of traffic generated (i.e., low delay for remote login or high throughput for file transfer). Given the PHB of the packet, each router between the source and destination RAS will serve or deliver the user""s packets according to the class of service described by the PHB marked in the packet. In this example, a packet marked with a PHB indicating low latency might be served before a packet marked for high throughput.
There is a great deal of latitude within the context of the framework for establishing different classes and subclasses of network traffic, as well as employing various queuing, forwarding and packet dropping disciplines. It is likely that traffic classification will be based on both technical and administrative concerns.
Regardless of the particular classes of service, each packet must be stamped with an appropriate PHB to indicate the classes of service of the packet. This stamping of the PHB in a packet may occur in many different places in the network, for example, at the user""s initiating workstation, a remote access server providing access to users, a first-hop router, a gateway or even other places within the network. A packet may also be stamped with a PHB more than once as it travels across different networks owned by different entities. For security and accountability purposes, it may be desirable to limit the stamping of the PHB of packets in devices controlled by the users.
Naturally, any sort of service differentiation must be accompanied by an appropriate pricing scheme so that users will act efficiently with respect to the priority level they chose and thus the network resources that they consume. Network service providers are currently seeking more latitude in their service contracts with users. Implementing a differential service scheme according to pricing will give them this latitude.
While there is a great deal of debate today currently focused on stamping and restamping issues, RAS devices will play a major role in supporting multiple service classes. Needed is a system and method to efficiently implement stamping and management of PHB service levels in RAS devices.
In accordance with an illustrative embodiment of the invention, a method and device for implementing differential packet delivery services through a packet-based network is provided. According to the illustrative embodiment, a remote access server (xe2x80x9cRASxe2x80x9d) device provides differential packet delivery through the network according to a xe2x80x9cper-hop behaviorxe2x80x9d or Differential Service Code Point (DSCP) field within the transmitted packets.
According to an aspect of the invention, the RAS device receives and interfaces a variety of different types of connections accessing the network such as data connections from the PSTN or from other networks. The RAS device is capable of marking packets transmitted to the network with the appropriate DSCP to provide a desired class of service as the packet is transmitted through the network.
According to another aspect of the invention, a RADIUS or DIAMETER server maintains the class of service for various users accessing the network. In an exemplary embodiment, the RADIUS/DIAMETER server maintains the appropriate DS bytes associated with each user. The DS byte contains the DSCP indicating the appropriate class of service for a user. The RAS device accesses the RADIUS/DIAMTER server device to obtain the appropriate DS byte to mark the packets for a particular user.
In addition, according to other aspects of the invention, a variety of other methods for marking packets according to other criteria such as on a per-modem basis can also be implemented.
The present embodiments allow users to select a desired class of service according to the particular requirements of the network application or user. For example, network applications with real-time delivery or large bandwidth requirements can specify and receive the appropriate packet delivery service to implement the desired service. The ability to control and charge applications and users fees according to the network resources they consume provides the ability to efficiently allocate and utilize network resources.